Switching device



y 1937. G. MATEJKA 2,086,628

' SWITCHING DEVICE Filed April 10, 1955 53 54 40 FIG./

a9 39 45 39 1a 26 I8 /2 I l/ 44 44 I Z6 29 36 0 s IQ' DIQ'EI a )L/ \Bllq INVENTOR a. MATE ATTORNEY Patented July 13, 1937 UNITED STATESPATENT OFFICE SWITCHING DEVICE New York Application April 10, 1935,Serial No. 15,511

3 Claims.

This invention relates to electric switching devices and particularly toswitching devices of the type used in connection with aircraft radioreceivers.

5 Though the conventional type of electric circuit controller orelectromagnetic relay is generally called upon to satisfy precisecircuit requirements, the switching device which functions in connectionwith aircraft radio equipment is 10 confronted with requirements of amore exacting nature.

A relay or switching device of this type should be so designed as topermit reasonable spacing of the various circuits it controls in orderto 15 guard against any interaction thereof caused by close coupling;the contact elements should be of such a construction as to introduce nocapacity effects when the relay is operated and the contact operatingmechanism should be of such a 2 nature as to insure a high degree ofcontact pressure under conditions of serious vibration to which therelay is subject.

It is the'object of this invention to provide a simple, compact anddurable switching device for 25 aircraft radio equipment which satisfiesthe requirements set forth above.

This object is attained in accordance with a feature of the invention bythe provision of relatively small movable contacts which are collec- 30tively mounted on a movable member of insulating material and adapted tobe brought into engagement with their respective coacting stationarysprings.

Another feature of the invention resides in a pantagraph mechanisminterposed between the magnet plunger and the stationary springs andwhich, in part, constitutes the movable contact carrier and by virtue ofwhich a wiping, vibrationless contact between the movable and station-.

40 ary contacts is effected.

A further feature of the invention provides for a suitable separation ofthe stationary contacts with which the circuits controlled areassociated, thereby preventing electrical coupling of 45 the variouscircuits.

These and other features of the invention will be readily understoodfrom the following detailed description made with reference to theaccompanying drawing in which:

50 Fig. 1 shows a plan view of the switch in the normal or unoperatedposition;

Fig. 2 shows a side elevation of the switch with a part of the base cutaway; and

Fig. 3 shows a vertical section on the line 3-3,

55 Fig. 2, with certain parts removed.

' Referring to the drawing more particularly, I

is a base member of aluminum or other lightweight material, upon whichthe relay structure of this invention is supported. Upon one end portionof the base I0 is mounted a solenoid ll 5 encased in a metal shield I2.The solenoid plunger I3 has one end thereof normally protruding from thesolenoid II and pivotally associated with the link l4 which constitutesone element of a pantagraph mechanism.

The pantagraph mechanism is made up of the links i4 and 25 and thecross-bar 24. The links H and 25 are trough-like in appearance and haveeach one end thereof pivotally secured between a pair of frame lugs l8,one pair of which is located on the base i0 immediately ahead of thesolenoid I2 and the other pair near the end of base l0 furthest from thesolenoid. The bar 24 which is of an insulating material, such asphenolized linen, pivotally interconnects the other ends of the links l4and 25. The pivotal connection between the various elements of thepantagraph mechanism and between certain of such elements and their basesupports or frame lugs l8 and the plunger i3 are made by means of 25hearing pins 26, washers 21 and cotter pins 28, the connection betweenthe pantagraph mechanism and the solenoid plunger being made atsubstantially the mid-point of the link I4.

From the description thus far, it is apparent that any movement of thesolenoid plunger l3 will be experienced by the pantagraph mechanismcomprising elements i4, 24 and 25. As viewed in Figs. 1 and 2, thepantagraph mechanism moves to the right under the influence of thesolenoid plunger Hi When the solenoid H is energized and to the leftunder the action of restoring spring 34 which has one end thereofsecured to frame lug 4| and the other end to the link l4. A stop 36mounted on the upper side of 40 the shield i2 has a slotted portionthereon extending out over one end of the bar 24 upon which is mounted afinger 35 which moves in the slotted stop upon the actuation of thepantagraph. The return movement of the pantagraph, under the influenceof spring 34, and accordingly the normal position of the pantagraph aregoverned by the position of the stop 36 with respect to the finger 35.

The bar 24 is equipped with a plurality of con- 60 tacts 31, three pairsbeing shown in Figs. 1 and 2,

each pair being suitably spaced so as to prevent interaction from closecoupling. These contacts are firmly secured to the underside of bar 24and may consist of metal pins 29 to each of which a 45 4a to the baseIn.

disc of contact metal such as platinum or other precious metal iswelded.

The base is provided with two integral upright projections or supports15 to which there is 5 secured a bracket 40 of insulating materal, suchas phenolizcd linen, by means of screws 53, washers 54 and lock nuts 55,as shown. Three contact springs 39 are suitably spaced with respect toeach other and to contacts 31 and are firmly attached to the undersideof bracket 40 by means of screws, washers and clamp plates asillustrated in Fig. 3. Each spring 39, which may be of nickel-silver orany other suitable material, carries at its end a contact 38 of platinumor other precious metal. The bracket 40 is so disposed with respect tothe pantagraph bar 24 that the contact 38 on spring 39 normally engagesone of the contacts 31 of each of the three groups of contacts on thebar 24. The contacts 31 of each pair of contacts are so spaced that themating contact 38 engages one contact 31 before being entirelydisengaged from the other contact 31 when the bar 24 is actuated. Inother words, a make-before-break engagement between con- 25 tact 38 andcontacts 31 is effected. At the extreme end of the movement of bar 24 tothe right or to the left, contact 38 is in engagement with but onecontact 31 of a pair. The springs 39 are pretensioned so as to insureproper pressure be- 0 tween the contacts 38 and 31.

Each contact 31 is provided with a terminal lug 43 and flexible lead 44for connection to an external circuit. The lead from the right-handcontact 31 of each pair of such contacts passes through a fanning strip45 of insulating material, such as phenolized linen, which is secured tothe base ID. The leads from the left-hand contact 31 of each pair ofsuch contacts is attached to a terminal 46, three such terminals beingshown. Each terminal 46 is mounted on a piece of insulation 41 which isfirmly secured to the base 10 in any suitable manner.

A metal shield 48 is secured to the bar 24 and is electrically connectedby means of flexible lead The shield 49 prevents electrical couplingbetween adjacent pairs of contacts 31 as well as between adjacentcontact springs 39 between which the shield extends.

The extent of the movement of the iron plunger 50 I3 in the solenoid IIis governed by an iron, threaded adjustable stud 49 which extends intothe solenoid. Lock nut 50 is employed to hold stud 49 in its adjustedposition.

Electrical connection to the solenoid I l is made 55 by means of thelead 52.

The relay of this invention has particular utility in connection withaircraft radio receivers in providing, for example, means for efiectingthe instantaneous switching between any frequency to .0 which thereceiver may be tuned and a particular landing beam frequency whichenables the pilotto correctly maneuver his plane in eilecting a landing.'In Fig. 1, the right-hand terminal or contact 29 of each of the threepairs of movable contacts will be connected to the regular tuningcircuit of the radio receiver and with the solenoid ll deenergized, thetuning circuits are connected to the receiver by way of the contact 70springs 39. Should it be necessary to effect a landing, the solenoid IIwill be energized in any well-known manner to cause the left-hand con- 1tact 29 of each pair of movable contacts to be moved into engagementwith the stationary contact springs 39 in place of the right-handcontact 29. This shift of contacts substitutes different tuning circuitsfor the regular tuning circuits of the receiver which are pre-tuned tothe particular frequency of the landing beam. Such a switching expedientenables the pilot to instantaneously condition the receiver for pickingup the landing beam frequency without disturbing the setting of theregular tuning circuit.

In order to guard against interaction of the various circuits caused byelectrical coupling, the 10 stationary springs 39 are widely separatedfrom each other, as are also the other terminal points of the severalcircuits.

The shield 48, shown interposed between the center and left-hand pairsof contacts 29, pre- 15 vents electrical coupling between these adjacentpairs of contacts. The movable contacts 31 are relatively small therebyintroducing no capacity effects when the relay is operated. The contactsprings 39 are of'such dimensions as to insure and maintain a highdegree of contact pressure under conditions of serious vibrations andthe sliding engagement of the contact elements insures clean contactingsurfaces as well as positive non-chattering contact. 25

What is claimed is:

1. An electromagnetically operated switch comprising a base plate, asolenoid mounted on said base plate and having a plunger movable in thedirection of the longitudinal axis of said base 30 plate, a contactcarrier, a link pivotally connecting one end of said carrier with saidbase plate, a second link pivotally connecting the other end of saidcarrier with said base plate and having its mid-point pivotallyassociated with the plunger of 35 said solenoid whereby any movement ofsaid plunger is transmitted to said contact carrier, a plurality ofspaced stationary springs disposed at right angles to said contactcarrier and mounted on said base plate, a contact mounted on each 0 ofsaid springs and normally tensioned against a corresponding one of thecontacts on said contact carrier whereby any movement of said carrierresults in a wiping engagement of'said contacts, and means forelectrostatically se arating adjacent contacts from each other, sa dmeans comprising a shield interposed between adjacent stationary springsand mounted on and movable with said contact carrier.

2. An electromagnetically operated switch comprising a base plate, asolenoid mounted on said base plate and having a plunger movable in thedirection of the longitudinal axis of said base plate, a contactcarrier, a link pivotally connecting one end of said carrier with saidbase plate, a second link pivotally connecting the other end of saidcarrier with said base plate and having its mid-point pivotallyassociated with the plunger of said solenoid whereby any movement ofsaid plunger is transmitted to said contact carrier, 9. plurality ofspaced stationary springs disposed at right angles to said contactcarrier and mounted on said base plate, a contact mounted on each ofsaid springs andnormally tensioned against a corresponding one of thecontacts on said contact carrier whereby any movement of said carrierresults in a wiping action between said contacts, a shield interposedbetween adjacent contacts and mounted on said carrier for preventingelectrical 7o coupling of the circuits associated with said contacts,and a flexible lead connecting said shield to said base plate.

3. An electromagnetically operated switch particularly adapted forservice with aircraft radio receiving equipment,'comprising a baseplate, a

' solenoid mounted on said base plate, an electro- 5 being movable inthe direction oi. the longitudinal axis of said base plate, aninsulating contact carrier, a link pivotally connecting one end oi. saidcarrier with said base plate, a second link pivotally connecting theother end of said carrier with said base plate and having its mid-pointpivotally associated with the plunger 0! said solenoid whereby anymovement of said plunger is transmitted to said contact carrier, aplurality of widely spaced stationary springs disposed at right anglesto said contact carrier and supported by said base plate, a contactmounted on each of said springs and normally tensioned against acorresponding one of the contacts on said contact carrier whereby anymovement of said carrier results in a wiping action between saidcontacts, .a shield interposed between adjacent contacts and mounted onsaid carrier for preventing electrical coupling of the circuitsassociated with said contacts. a spring for maintaining said plunger andsaid, .rrier in normal position and against whose action said plungeroperates to actuate said contact carrier and means including a pinmount- I ed on said carrier and a slotted element mounted on the shieldhousing said solenoid, for limiting the longitudinal movement of saidcarrier and preventing side play thereof during its actuation.

GLADSTONE MATEJKA.

